genirq: Allow the irqchip state of an IRQ to be save/restored

[mirror_ubuntu-zesty-kernel.git] / kernel / irq / manage.c

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c0a1100d911f5503681fc062815fbb4a2f34234b..e68932bb308e96e1c6aa184dc7d9972fba8df06e 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1798,3 +1798,94 @@ int request_percpu_irq(unsigned int irq, irq_handler_t handler,
 
        return retval;
 }
+
+/**
+ *     irq_get_irqchip_state - returns the irqchip state of a interrupt.
+ *     @irq: Interrupt line that is forwarded to a VM
+ *     @which: One of IRQCHIP_STATE_* the caller wants to know about
+ *     @state: a pointer to a boolean where the state is to be storeed
+ *
+ *     This call snapshots the internal irqchip state of an
+ *     interrupt, returning into @state the bit corresponding to
+ *     stage @which
+ *
+ *     This function should be called with preemption disabled if the
+ *     interrupt controller has per-cpu registers.
+ */
+int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
+                         bool *state)
+{
+       struct irq_desc *desc;
+       struct irq_data *data;
+       struct irq_chip *chip;
+       unsigned long flags;
+       int err = -EINVAL;
+
+       desc = irq_get_desc_buslock(irq, &flags, 0);
+       if (!desc)
+               return err;
+
+       data = irq_desc_get_irq_data(desc);
+
+       do {
+               chip = irq_data_get_irq_chip(data);
+               if (chip->irq_get_irqchip_state)
+                       break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+               data = data->parent_data;
+#else
+               data = NULL;
+#endif
+       } while (data);
+
+       if (data)
+               err = chip->irq_get_irqchip_state(data, which, state);
+
+       irq_put_desc_busunlock(desc, flags);
+       return err;
+}
+
+/**
+ *     irq_set_irqchip_state - set the state of a forwarded interrupt.
+ *     @irq: Interrupt line that is forwarded to a VM
+ *     @which: State to be restored (one of IRQCHIP_STATE_*)
+ *     @val: Value corresponding to @which
+ *
+ *     This call sets the internal irqchip state of an interrupt,
+ *     depending on the value of @which.
+ *
+ *     This function should be called with preemption disabled if the
+ *     interrupt controller has per-cpu registers.
+ */
+int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
+                         bool val)
+{
+       struct irq_desc *desc;
+       struct irq_data *data;
+       struct irq_chip *chip;
+       unsigned long flags;
+       int err = -EINVAL;
+
+       desc = irq_get_desc_buslock(irq, &flags, 0);
+       if (!desc)
+               return err;
+
+       data = irq_desc_get_irq_data(desc);
+
+       do {
+               chip = irq_data_get_irq_chip(data);
+               if (chip->irq_set_irqchip_state)
+                       break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+               data = data->parent_data;
+#else
+               data = NULL;
+#endif
+       } while (data);
+
+       if (data)
+               err = chip->irq_set_irqchip_state(data, which, val);
+
+       irq_put_desc_busunlock(desc, flags);
+       return err;
+}